Free multi-color decks can be made with the free cards that make up the starting decks.
From the main menu, choose the collection icon in the lower right panel. This gives you all available decks, cards, and the option to look at and create decks. Just click "new" to get started creating a deck and don't forget to save it.
Below are viable options for making a multicolor deck. These decks can/should be improved by switching out better cards from the free booster (random) that every player receives.
A full free card list is included for totality.
Click on the combination for a complete description:
|/ Blue||/ Black||/ Red||/ Green||/ Black|
|/ Red||/ Green||/ Red||/ Green||/ Green|
Free card list
There are 196 free cards, not including the free booster pack.